Drum hoops, or rims, are needed to hold a drum head in place and apply even tension to the drum head for tuning. Most drum hoops are die cast, wood or flanged.
Die cast drum hoops are made by pouring molten metal into a mold having the shape and size desired for a finished drum hoop. Die cast drum hoops usually provide a thicker, and therefore stronger, rim than flanged hoops which allows the drum head to be more evenly tuned because the die cast hoop is often more responsive through a tuning range. However, die cast hoops have limited flex and may therefore make the drum more difficult to tune when a drum shell, to which the drum hoop is attached, or the head is not completely round due to the limited amount of flex.
Wood drum hoops can be rigid or flexible depending on how they' are made. As a result, wood drum hoops may have tuning features similar to those of die cast drum hoops if the wood drum hoop is constructed to be more rigid or may have tuning features similar to those of flanged hoops if the wood drum hoop is constructed to be more flexible. An interesting feature of wood drum hoops is that they will absorb vibration and act like an extension of the drum shell which gives the drum a bright resonance.
The most common type of drum hoop is the flanged drum hoop which is usually comprised of metal of varying thickness. The hardness of the metal will have an affect on the sound and the ability to tune the drum. Flanged drum hoops are usually made by folding a strip of metal to create a series of bends of approximately 90 degrees called “flanges.” Most modern drum hoops have three bends and are therefore referred to as “triple-flanged” hoops. The folding of the metal strips is usually done by stamping the metal. The stamped metal is then made into a circle and welded at adjoining ends. Holes are punched into the metal to receive tension rods which pass through the hoop and screw into lugs attached to the body of the drum.
In a conventional drum, an annular drum hoop is provided at an end of the drum body and a drum head is fixed over an open end of the drum body by a drum hoop. The hoop may have a diameter which is slightly larger than the diameter of the drum body and is installed on the drum body such that the hoop presses on a bead around the periphery of the drum head. The hoop is generally fixed to the drum body by a plurality of lug bolts which are screwed into and tightened in threaded holes in respective lugs which are arranged around the drum body. Tension on the drum head is adjusted by adjusting the tightening length of the various lug bolts.